Electromagnets and Solenoids

Explain flemings hand rules

We use the left hand (negative to positive, actual)

• thumb is the current

• fingers are direction of magnetic field

both hands the thumb and fingers mean the same, the difference is the direction of current that the thumb points to

Strength of electromagnets and solenoids

• Number of loops (more loops = more strength)

• Current strength

• Core (electromagnet) or no core (solenoid)

Effectiveness of solenoid or electromagnet

• Length (number of loops)

• Diameter (closer to coil = more strength)

• Current (more power = stronger)

3 ways to induce secondary current

• Move the conductor

• Move the magnetic field

• Vary the flux strength (AC ONLY)

4 things that govern strength of secondary current

• Strength of magnetic field

• Motion (speed)

• Angle

• Number of turns

solenoid

coil with a current

how to make an electromagnet stronger

wrap wire around iron core